William s



No. 620,308. 1 Patented Feb. 28, I399.

W. S. HADAWAY, JR.

" lNGANDESCENT ARC LIGHT.

(Applicatz'bn filed Feb. 1a; 1598.

6N0 Model.)

N ww

j Z 6' mi.- 0%.

sion and contraction by changes of temperature.

no casing of metal or analogous substance to sustain it about the electrodes, but is of sufficient strength and durability to be supported ;-who1ly by the electrodes, and no obstruction TI-UNITED. STATES PATENT @F ics.

WILLIAM SLHADAWAYI. JR., on NEW YORK, n. Y.

INCANDES'CENT ARC=LIGHT.

' sracirroArron fdrming m a Letters Patent No. cameos, dated February 28,1899.

' Application filed Pebrusrylfi, 1898. Serial ll'o. 670,511- (ll'o model.) I

To all uihom' it may concern.- I

. 3e it known that I, WILLIAM S; HADAWAY,

Jr., a citizen of the United States, residing at New York, county of New York, State of New York, have invented certain new and useful ing specification and the accompanying draw-' ings, forminga part of the same. Y I

. towhich it is subjected; Such sleeveis made,

. in the electric arc and which isthus reduced The present invention is based upon the discovery that" an 'unperfo'ratedsleeve with a bore fitted closely to the carb'onelectrodes canbe made of such material as to be rendered incandescent by the arc andwithout essential change or disintegration by the heat of crystallized magnesia which has been fused to a condition of the highest density, '50 that it is no longer subject to appreciable expan- With such material the sleeve requires thus exists about the sleeve to. prevent the difiusion of the light therefrom. Incidentally the use of such incandescent sleeve operates to reduce the brillianoy of the light and to increase its difiusion, while thecircu lar form of the sleeve and the absenc'c'of any sis metallic casing permits the d-ifiusionof the ground to powder and mixed. in a plastic mass with magnesium chlorid, the mixture being then molded under heavy pressure into the required shape. 7

With cylindrical electrodes like the carbon pencils in ordina y use the sleeve is made of tubular form, with bore adapted to permit the adjustment of one of the pencils within the sleeve to maintain the arc. The sleeve is preferably secured by-atight joint to one of exclude air from the are. With this construction the space between the carbons is when the lamp is in operation filled with gases of a high temperature, whichiolfer far less resistance to the are than the atmosphere, andthe carbonsmay thusbe separated to a greater degree'and an arc of greater-length be anai-ntained.

"The heatot-thearc operates upon the encircling sleeve. to raise the material. of the same to incandescence, and the lamp thus produces-a light which is derived in part from the incandescenceo'fthe sleeve and inpartfrom: the arc whose light is transmitted through the wallsof theshell.

When the sleeve is attached to the upper carbonaud movable upon the lower carbon,

the heatedgases between the carbons are wholly prevented from escaping, as they are of much less density than the atmosphere, which thereforetends to push them upward.

As they cannot escapeup'wardly, the airis prevented from entering and circulating" about the are or reducing its temperature. A tern perature is .thus easily maintained which heats the sleeve to incandescence and -pro- 'duces alight combining the qualities of the 'lbngitudinallyor transversely.

The invention-will be understood by reference to the annexed-drawings, in which-- Figure 1 represents the. carbonsadjacent to the arcwitli the sleeve in section inclosin'g thespace between the carbon points. Fig. 2 is-an end view of the sleeve, and Fig. 3 a side elevation of the same when made of cylindrical shape. Fig. ii is a diagram showing an arc-lamp with the sleeve fitted about the carbons, and attached to the upper carbon, as represented in Fig. 1. Fig. 5 represents a sleeve with a projecting belt to increase the diffusion of light; Fig. firepresents the carbon points with a sleeve in section about the same and having transverse corrugations. Fig. 7 is a side elevation, and Fig. 8 a plan, of asleeve having longitudinalcorrugations or ribs.

A designates the upper electrode, B the lower electrode, and O the sleeve surrounding them adjacent to the arc.

. carbon.

heated gases which are formed between the ends of the carbon tend to expel such air through the small space surrounding the lower As the temperature of the gases increases the arc may be increased in length owingto the diminution of their resistance; but such separation does not produce any admission of the air, as the gases which are generated are unable to escape.

The sleeve when formed of crystallized magnesia, as above described, may be made nearly transparent in character, so that the light from the arc is emitted freely through the same, and when the heat of the arc has rendered it incandescent the light is produced by radiation from the sleeve as well as from the arc.

When the sleeve is attached to one of th carbons, as shown in Fig. 1, the arc is 3dr, vanced toward one end of the sleeve 'bythe consumption of the carbon to which it is attached, and the point of greatest incandes cence therefore travels toward one end'of the sleeve during the use of the lamp. The sleeve ma ghowever, be held stationary, ifdesired,

' an in such case the arc may be maintained within a certain part of the sleeve, where it may be ribbed transversely, as shown in Fig. 5. When such rib becomes incandescent, it throws the light in adifferent direction-from the other portions of the sleeve. The same effect is producedin a greater degree with the construction shown in Fig. 6, where the sleeve is corrugated transversely, and the longitudinal ribs shown upon the sleeve in Figs. 7 and8 serve to diffuse the light in a still different manner. The cylindrical sleeve is of course best adapted to-be rendered incandescent at various points in its length, as its shape and diameter are uniform throughout.

It is obvious that the arc in my construction needs noglobe about itto protect it from the wind'or any extraneous interference, and

the lamp may therefore be operated without any globe; but a globe, as indicated by the dotted circle D in Fig. 4, may be uscd'with the lamp, if desired, the globe being made of clearglass to transmit the light orof ornamental charactor when such effects are desired.

It has been common heretofore to fit the ends of the carbons within a laterally-perforated block, so that the light of the arc may escape through the lateral opening, and'i't has also been proposed to confine an amorphous mass of zirconia about the ends of the earbons to be rendered incandescent by the arc but in all such constructions a metallic casing has been employed to support the incandescent material, and the diffusion of the light in every direction is thus prevented.

I have discovered that magnesia crystals possess properties altogether diflferent from calcined magnesia and other substances heretofore proposed for incandescent lighting by the are and that it possesses the greatest density of which the substance is capable, so that it is not subject to appreciable expansion and contraction with changes of temperature and is not disintegratedor cracked when applied to the carbons about the are. I am thus enabled to furnish a sleeve which requires no metallic casing, but which can be supported directly upon the carbons and which when heated by the arc is thus adapted to diffuse the light in all directions around such car bons. The use of this substance thus materially changes the conditions under which'an incandescent envelop can be employed about the arc, and as the substance possesses great durability it is obvious that it furnishes a verycheap and effective means for increasing the durability of the carbons by the exclusion of air and of distributing the light in a more diifused manner than is possible with the naked are.

Having thus set forth the nature of myinvention, what'I claim herein is-- 1. In an arc-light, the combination, with electrodes of uniform cross-section, of a refractory sleeve fitted close to the same about the arc, and adapted when the light is in operation to be heated to incandescence in prox imity to the arc.

2 in an arc-light, the combination, with the carbon pencils, of a refractory shell fitted close to the carbons about the arc to be heated thereby, and provided with a projection or projections to diffuse the light when the shell is incandescent.

3. In an arc-light, the combination, with- '5. An nnperforated sleeve, for an incaudescent arc-light, formed of fused magnesia and a suitable binder, substantially as herein set forth.

-e2d,aos' i y I 's' 6 In an arc-light, vthe, combination, with my hand in the piesence of two'snbscribing tllze carbgnfpengils, ofa tubllallimiperforatfld witnesses. s eeve 0 use ma 'nesia' tt c ose to 1; e pencils abouttharzandadapted tobe heated- 1AM A J 5 to incandescence by the same, substantially Witnesses:

as herein set forth. Tnoms S. CRANE,

In testimopy whereof I hav e ga ma set; Enwgnn F. KmgmY. 

